Brewvestigation..What went wrong?

Northern Brewer General
1

Hey all, need some collective brain power to point me to the problem. I had a failed batch after many many years of successful brewing, and it has depressed me to the point of canceling my weekend plans to make a redemption brew.

I brewed up a pale ale last weekend, and when I took a sample last night it had a smell and taste that I would describe as old, musty, dirty, cardboardy. It’s like the grain I used had been sitting in a basement for 5 years, and had been occasionally stepped on. My instincts would tell me that describes a brew that is oxidized, but it perplexes me on why that happened.

Instead of getting in to the nitty gritty of my whole process, let me tell you what I did differently this time.

1)I created a yeast starter, but realized I couldn’t brew two weekends ago, so I had to save it for the following weekend. Starter was on the stir plate for 48 hours. After that time I put it in the fridge with tin foil on top with a rubber band holding it. Starter stayed in fridge for 6 days until brew day. On brew day, I took it out, decanted MOST of the starter liquid, and let warm up. When I was about to pitch I vigorously shook the starter since the yeast cake was nice and compact, and I needed to break it up. Pitched into wort at 72F.

2)I used a brand new tank of O2 to oxegenate the wort. It was the small red canister that you can get at home depot, that is used for a welding torch. Is there such thing as bad oxygen?

3)Fermentation took off over night, per usual, and in the morning the fermentation was still at 72F, even though I hoped it dropped to 70. I wanted it to primary at 70, so I decided to lower the temp on my fermentation fridge. This dropped the temp down to 68 over a couple days. I would have much preferred to pitch at the appropriate temp to avoid this, but I couldn’t get my wort down low enough at the time. One thought is the temperature drop could have screwed something up, but 68F is still well within the range of the yeast (1056 btw).

4)The yeast had pretty much completely dropped out at 3 days, pretty much after the temp drop took place. This is WAYY faster then usual, so my concern was that the fermentation got stuck and the yeast froze up and dropped out due to the temp drop… hence the desire to take a gravity reading on day 4. Gravity was at 1.010, so at the very least the brew attenuated fully, which also seems fast.

So I’m pretty bummed out. I may have to toss the batch if the problem cant be remedied, and I was really excited because this was my first time using Mosaic hops and experimenting with FWH. I may brew a batch tomorrow to make myself feel better, but I want to close the book if possible on this batch.

Any thoughts as to what caused the off flavors? The starter I pitched did have some starter wort that was heavily oxidized, but it seemed to be in small concentrations and I generally always use a little left over liquid to help break the yeast cake up (although I have never had the starter on the plate for longer than 24 hrs, and I have never stored a starter for later use).

Thanks for your help

P.S. My GUESS is that it tastes oxidized, but I’m open to other issues (contamination?) if someone has a better grasp on this.

2

Do you normally primary in the upper 60s to low 70s? Are you measuring beer temp or ambient?

3

Normally primary around 68 70 for most american ales. I’m measuring the ambient beer temp, and have a temp controller and a stick on thermometer on a glass carboy.

4

Chaglund:
I know it doesn’t need to be said to someone with experience, but for the benefit of those with less experience;
Don’t give up on this batch after only 1 week in the fermenter. If I based final quality on my 1 week SG sample, I probably would have dumped at least a couple batches that ultimately turned out pretty good.
Keep the faith bro! :smiley:

5

The only thing about your whole process that seems suspect is the yeast starter in the fridge for 6 days… Your temps are all good and everything else looks fine.

My buddy had a stuck fermentation in an Oatmeal Stout because it was a high gravity one and he forgot to pitch more yeast to deal with the high OG. At any rate, his came out smelling and tasting like sour green apples, and was absolutely horrible at first. It took two months in the bottle, but by God, it cleared up and came out pretty tasty in the end. I wouldn’t worry so much about yours just yet, I doubt it’s contaminated, and yeast can do amazing things given enough time.

6

There is nothing wrong with storing your yeast starter for 6 days (or 2 months) before using. It very similar to the yeast being stored at the brewstore for 6 days to 5 months.

OP: You say you are measuring “ambient beer temp”. Generally considered ambient temp is the temp of the air, beer temp is the temp of the beer.

7

It seems unlikely to me that it would be oxidation… Generally oxygen is introduced during transfers to secondary, bottling bucket, kegs, etc… and gets worse over time. I just don’t see how that would have happened in primary fermentation.

  • How much oxygen did you put in your beer? I am assuming you used something like this to attach to your O2 tank??? Did it have a filter??
http://www.graintoglasshomebrew.com/pro ... system.htm

How long did you have the oxygen on??

*Temps maybe a bit on the high side… that, along with the beer being somewhat young could maybe cause some problems.

*You said it tasted like old grain… was it? Do you know how old the grain was? Do you buy by the sack or maybe you got some old grain from the store???

8

Also… what do you mean by:

“The starter I pitched did have some starter wort that was heavily oxidized, but it seemed to be in small concentrations and I generally always use a little left over liquid to help break the yeast cake up (although I have never had the starter on the plate for longer than 24 hrs, and I have never stored a starter for later use).”

That makes no sense to me… how can something be heavily oxidized … but in small concentrations??? Were you using old wort from some other batch??

I routinely leave starters on the stir plate for more than 24 hours… especially lager starters. I also agree that putting it in the fridge is not any big deal at all.

9

[quote=“chaglund”]I’m measuring the ambient beer temp, and have a temp controller and a stick on thermometer on a glass carboy.[/quote]If I’m reading this correctly, you’re using the temp controller to read the ambient (air) temp in the fridge and have it set to 68-70F? What’s the differential set to? For instance, if you have the temp set to 68F and the differential at +2F, you’re ambient temp rises to 70F and the fridge kicks on and cools ambient back to 68F and shuts down. And if you’re controlling the temp off ambient, rather than reading the beer temp, and you have it set at 68F, your beer temp could be as high as the mid-70s (fermentation creates heat), which can result in off-flavors.

10

[quote=“Nighthawk”]
OP: You say you are measuring “ambient beer temp”. Generally considered ambient temp is the temp of the air, beer temp is the temp of the beer.[/quote]

Sorry, not sure why I wrote it like that. Ambient temperature in the fridge.

[quote=“Braufessor”]* How much oxygen did you put in your beer? I am assuming you used something like this to attach to your O2 tank??? Did it have a filter??

http://www.graintoglasshomebrew.com/pro ... system.htm

How long did you have the oxygen on??

*You said it tasted like old grain… was it? Do you know how old the grain was? Do you buy by the sack or maybe you got some old grain from the store???[/quote]

Diffusion stone attached to O2 tank. Had it on for 1 minute. Grain is about 7 months old, originally bought in 55lb bag, stored in an airtight bucket.

[quote=“Braufessor”]
“The starter I pitched did have some starter wort that was heavily oxidized, but it seemed to be in small concentrations and I generally always use a little left over liquid to help break the yeast cake up (although I have never had the starter on the plate for longer than 24 hrs, and I have never stored a starter for later use).”

That makes no sense to me… how can something be heavily oxidized … but in small concentrations??? Were you using old wort from some other batch??[/quote]

I meant that the starter wort was heavily oxidized from being on the stir plate, and continued to aerate past fermentation (since it was on for 48 hours, it probably finished 12-24 hours into it). By small concentrations, i meant relative to the size of the batch it was pitched into. Wondering if a cup or two of oxidized wort into 5 gallons would make a noticeable difference.

Differential is set to two degrees (although it’s not all that accurate) on the ambient temperature. I set it at 70, so the compressor kicks on at 70 and lowers it to 68 (in reality 67/66), then turns off. Temp then rises to 70 and kicks on. I realize I should be controlling the beer temp, I just haven’t found a good way to do it yet.

Thanks for all the feedback. Gameplan is to sit on it a while longer and see what happens. Hopefully it will come out good in the end. I guess my thought was that the fridge is not the cleanest place in the world, and something went wrong with storing the starter in there for a week. The bizarre thing was that the yeast settled out in 3 days, which has never happened to me that fast. Just seemed like something was suspect.

Thanks again, you guys rock

11

What strain of yeast did you use? I would be willing to bet that you are tasting the yeast, and that they haven’t had time to clean up after themselves. I’ve had a batch or two that tasted really odd like that, but cleaned up very well over time.

(The one that had the most green apple/cardboard taste was a batch of grocery store cider with bread yeast. Tasted awful, like wet cardboard. After a couple of months it was really crisp and clean.)

12

You brewed this just 5-6 days ago correct?

I wouldn’t put much stock in a taste test at this point. Give it a few weeks.

13

[quote=“chaglund”]I realize I should be controlling the beer temp, I just haven’t found a good way to do it yet.[/quote]If your temp controller has a probe, you just put the probe against the side of the fermenter and tape a piece of bubble wrap over it to insulate. If you can, change the differential to 1F, too.

14

[quote=“Brick1083”]You brewed this just 5-6 days ago correct?

I wouldn’t put much stock in a taste test at this point. Give it a few weeks.[/quote]

Ahhhh, the voice of experience… I concur… Give her a taste after a couple of weeks and then decide if something went haywire.